Does cost sharing really reduce inappropriate prescriptions?

This paper explores different empirical strategies to examine the effect of cost sharing for prescription drugs in some dimensions of medication-related quality, namely the probability of inappropriate prescription drug use among United States seniors. Using data from 1996 to 2005, we explore various specifications that correct for sample selection, endogeneity¸ and unobserved heterogeneity. We find a small, but measurable, negative price elasticity for inappropriate drug use with respect to self-reported average out-of-pocket costs for all drugs consumed. That is, user fees reduce the use of potentially inappropriate medications, however the elasticity of cost sharing is lower than that of drugs in general and the price elasticity is relatively close to zero, suggesting that any quality improvements from co-payments are small

Test of the fluctuation theorem for stochastic entropy production in a nonequilibrium steady state

We derive a simple closed analytical expression for the total entropy production along a single stochastic trajectory of a Brownian particle diffusing on a periodic potential under an external constant force. By numerical simulations we compute the probability distribution functions of the entropy and satisfactorily test many of the predictions based on Seifert's integral fluctuation theorem. The results presented for this simple model clearly illustrate the practical features and implications derived from such a result of nonequilibrium statistical mechanics.Comment: Accepted in Phys. Rev.

Tilted excitation implies odd periodic resonances

This work was supported by the Brazilian agencies FAPESP and CNPq. MSB also acknowledges the Engineering and Physical Sciences Research Council grant Ref. EP/I032606/1. GID thanks Felipe A. C. Pereira for fruitful discussions.Peer reviewedPostprin

Does Cost Sharing really Reduce Inappropriate Prescriptions?

This paper explores different empirical strategies to examine the effect of cost sharing for prescription drugs in some dimensions of medication-related quality, namely the probability of inappropriate prescription drug use among United States seniors. Using data from 1996 to 2005, we explore various specifications that correct for sample selection, endogeneity¸ and unobserved heterogeneity. We find a small, but measurable, negative price elasticity for inappropriate drug use with respect to self-reported average out-of-pocket costs for all drugs consumed. That is, user fees reduce the use of potentially inappropriate medications, however the elasticity of cost sharing is lower than that of drugs in general and the price elasticity is relatively close to zero, suggesting that any quality improvements from co-payments are small.

How to avoid microaspiration? A key element for the prevention of ventilator-associated pneumonia in intubated ICU patients

Microaspiration of subglottic secretions through channels formed by folds in high volume-low pressure poly-vinyl chloride cuffs of endotracheal tubes is considered a significant pathogenic mechanism of ventilator-associated pneumonia (VAP). Therefore a series of prevention measures target the avoidance of microaspiration. However, although some of these can minimize microaspiration, benefits in terms of VAP prevention are not always obvious. Polyurethane-cuffed endotracheal tubes successfully reduce microaspiration but high quality data demonstrating VAP rate reduction are lacking. An analogous conclusion can be made regarding taper-shaped cuffs compared with classic barrel-shaped cuffs. More clinical data regarding these endotracheal tube designs are needed to demonstrate clinical value in addition to in vitro-based evidence. The clinical usefulness of endotracheal tubes developed for subglottic secretions drainage is established in multiple studies and confirmed by meta-analysis. Any change in cuff design will fail to prevent microaspiration if the cuff is insufficiently inflated. At least one well-designed trial demonstrated that continuous cuff pressure monitoring and control decrease the risk of VAP. Gel lubrication of the cuff prior to intubation temporarily hampers microaspiration through sludging the channels formed by folds in high volume-low pressure cuffs. As the beneficial effect of gel lubrication is temporarily, its potential to reduce VAP risk is probably nonsignificant. A minimum positive end-expiratory pressure of at least 5 cmHO can be recommended as it reduces the risk of microaspiration in vitro and in vivo. One randomized controlled study demonstrated a reduced risk of VAP in patients ventilated with PEEP (5-8 cmHO). Regarding head-of-bed elevation, it can be recommended to avoid supine positioning. Whether a 45° head-of-bed elevation is to be preferred above 25-30° head-of-bed elevation remains unproven. Finally, the routine monitoring of gastric residual volumes in mechanically ventilated patients receiving enteral nutrition cannot be recommended

Tight coupling in thermal Brownian motors

We study analytically a thermal Brownian motor model and calculate exactly the Onsager coefficients. We show how the reciprocity relation holds and that the determinant of the Onsager matrix vanishes. Such condition implies that the device is built with tight coupling. This explains why Carnot's efficiency can be achieved in the limit of infinitely slow velocities. We also prove that the efficiency at maximum power has the maximum possible value, which corresponds to the Curzon-Alhborn bound. Finally, we discuss the model acting as a Brownian refrigerator